With regard to conventional examining apparatuses and examining methods for detecting defects present on the surfaces of objects to be examined such as semiconductor wafers it has been disclosed in JP-A-2001-208694 (Patent Literature 1) that an exposure time of a photoelectric device is varied in addition to varying the number of added lines in processing of a sample image by TDI based on a light image magnification such that the number of added lines is decreased when an incident light amount is large in a low magnification and the number of added lines is increased when the incident light amount is small in a high magnification. Further, JP-A-2002-39960 (Patent Literature 2) has disclosed that a charge accumulation time can be changed and the number of stages can also be switched over as a multi-tap configuration by using a TDI sensor of variable stages. Furthermore, JP-A-2004-301751 (Patent Literature 3) has disclosed that the number of accumulation stages for a transmitted light sensor and the number of accumulation stages for a reflected light sensor are made different (or can be specified) by using the TDI sensor as a transmitted light sensor and a function to be able to adjust a luminance, an expansion and contraction (magnification), a distortion, and a rotation can be provided to either image. In the similar examining apparatus, JP-A-2006-84189 (Patent Literature 4) has disclosed that a scan speed is made high in using a high magnification lens and is made low in using a low magnification lens when moving an imaging unit to scan the object to be examined and that a camera unit has a TDI sensor and a lens switching device to control a moving speed in response to switching over the high and low magnification lenses. Moreover, JP-A-2000-105203 (Patent Literature 5) has disclosed that a TDI sensor is used as an image sensor and a determination criterion can be set in an image processing unit depending on an area priority mode, a standard mode, and a sensitivity priority mode.